This week is the 40th anniversary of President Richard Nixon's announcement of his resignation on Aug. 8, 1974. I'm going to mark the occasion with a few posts. I used to do a 40-year anniversary "live" blog of Watergate ... I think it's one of the greatest stories in U.S. political history, for pure entertainment value but also because it holds some very important lessons about how the U.S. political system and the presidency really work. So I have plenty to say about it.

First things first, however: I'll start with a basic primer of what "Watergate" really was.

Watergate was a huge conspiracy by the Nixon administration and his re-election campaign to undermine U.S. democracy that was driven straight from the Oval Office and conducted by White House and campaign personnel. Broadly speaking, there were two parts of that abuse of power. The first, associated with the "plumbers" and the break-in at Daniel Ellsberg's psychiatrist's office, was intended to quash domestic dissent; the other, associated with the break-in and bugging of the Democrats' offices at the Watergate, attempted to manipulate the opposition party.

The Watergate cover-up (and then, after the initial cover-up was exposed in early 1973, the cover-up of the cover-up) was an extraordinary obstruction of justice personally supervised by (and in 1973 and 1974 often conducted by) the president of the United States himself along with the White House senior staff. It involved destroying evidence, organized perjury and payoffs to witnesses, infiltration of the Justice Department, the misuse of other government agencies to block legitimate investigations, and more.

On top of that, Nixon had already alienated Members of Congress, bureaucrats and political appointees in the executive branch, the press, and both political parties by violating the basic norms of the political system. He was overly ruthless to his political foes, wasn't loyal to those who could have been his political friends, and lied constantly to both. All of which was far from standard behavior within national politics (though not, in some ways, all that different from the way his predecessor, Lyndon Johnson, acted).

Not everything done was illegal, and not every illegal thing that was done was directly ordered by the president. But enough of it was illegal, and the president was sufficiently involved, that when much of it was exposed (plenty still remained hidden in 1974) the president resigned in the face of certain impeachment and almost certain conviction by overwhelming, bipartisan votes. Those who went to jail over it included the president's chief of staff, top domestic policy staffer, top political staffer and White House counsel, in addition to top campaign staff and others. The president, had he not been pardoned, probably would have joined them; there's no doubt he was guilty of numerous felonies.

Don't be fooled by those who consider Watergate a minor matter. It contained major and minor crimes, and proved the president absolutely unfit for office.

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